Safety release clutch



` Nov. 18, 1947. R. G. BROWN 2,431,107

s AFETY RELEASE CLUTCH FiledJan. 12, 194e 2 sheets-sheet 1 Im/eiltor @www www@ mm Nov. 18, 1947. R. G. BROWN SAFETY RELEASE CLUTCH Filed Jan. 12 1946 2 Sheets-Sheet 2 Inventor ,Qa/.S f faw/z Patented Nov. 18, 1947 UNITED STATES Artnr orner.

SAFETY RELEASE CLUTCH ,Bush G.- Brown, Riverten, Wye- Appliation January 12, 1946, Serial No. 640,767

Glaims.- 1

This application is a continuation, in part, of my eo-periding application for U. S. Letters Pat.- ent, Serial Ivo/558,177, filed VOctober 11, 1944, upon Reciprocating saw machine.

The present invention relates to improvements in clutches of the type embodying internal ex..- panding clutch shoes, and wherein the shoes are expanded by mechanical means and contracted or released by springs.

An important object of the invention is to provide a clutch of the above kind which is comparatively simple and durable in construction, and highly efficient in operation.

Another important object is to provide a clutch of the above kind wherein means is provided to automatically contract and release the clutch shoes so as to free the body of the clutch from a driven shaft onV which it is journaled, when rotation of said shaft is resisted to a, predetermined extent by an excessive load.

The present invention consists in the novel form, combination and arrangement of parts hereinafter more fully described, shown in the accompanying drawings and claimed.

In the drawings:

`Figure l is a view partly in vertical section and partly in side elevation, of a clutch con.- structed in accordance with the present invention and having a body in the form of a power transmitting pulley.

Figure 2 is a view partly in plan and partly in section on line 2..-,2 of Figure 1.

Figure 3, is a view partly in elevation and partly in section yon line 3-3 of Figure l.

Figure 4 is a fragmentary section taken on line 4-4 Q f Figure l.

Referring in detail to the drawings, 5 indicates a driven ,Shaft journaled in a torque tube 5a, and 6 a pulley which is suitably driven and which is journaled on the shaft 5, novel means being provided in accordance with the present invention for releasably clutching the pulley 6 to the shaft 5 for driving the latter.

As shown clearly in Figures 2 and 3, an end portion of the shaft 5 has a part I thereof reduced and provided with longitudinal keys B which are received in internal grooves of a sleeve 9 vso that said sleeve is splined on said part 'I o f the shaft. Sleeve 9 is secured in place by a rivet IU which passes through said sleeve and the shaft part 'I and has heads countersunk in the surface of the sleeve 9 as indicated by dotted lines in Figure 3. The end portion of shaft 5 has another part II which is reduced still further and which has accurately fitted and journaled thereon a sleeve l2 forming the hub of a disc I3. The terminal part I4 of the end portion of shaft 5 is still further reduced and threaded to receive a nut I5 which is locked in adjusted position on the shaft part M by a cotter pin IS. The pulley 6 is provided with a hub I'i in which are fitted the outer conical races I8 of a pair of roller bear,- ings which also include inner races I9 fitted on the sleeve I2, and bearing rollers 2l! interposed between the races I 8 and I9. The inner race I9 of one bearing projects beyond an end of ther shaft part I I about the adjacent portion of the shaft part Iii. This projecting race I9 is engaged by a washer 2l loosely placed on the shaft par-t I4 between said race and the nut I5. Consequently, adjustment of nut I9 eifects adjustment of the adjacent race I9 so as to shift the pulley i5 and the outer races I8 and thereby avoid any unnecessary play in the bearings. It will be noted that the bearings are spaced apart so as to pro.- vide a chamber in the hub i7 between them for the reception of grease, the hub being provided with a grease gun fitting 22 to facilitate introduc.- tion of grease in this chamber for lubricating the bearings. Escape of lubricant from the hub I7 is prevented by means of grease retainers 22 fitted in the ends of the hub Il and on the outerl ends of the races I 9. A thrust washer 23 is fitted on the shaft part il between the adjacent end of sleeve 9 and the disc I3.

The rim of pulley 6 preferably has a crowned outer surface and is extended at one side to form the drum of the clutch. The disc I3 is arranged within the rim of the pulley G at one end of its hub Il' or between the hub I 'l and the sleeve 9. Arranged at the inner side of disc I3 adjacent the periphery of the latter and in position to engage the inner surface of the rim of pulley Ei are clutch shoes 24 which are connected at corresponding ends to the disc I3 by links 25. Sleeve 3 forms the hub of a driving spider or cross-bar having oppositely projecting arms 2S, each of which is composed of a pair of spaced rigidly connected members. Turning movement of the spider in one direction relative to disc I3 is limited by stop blocks 2l xed to and projecting late erally from the disc I3. Fixed to disc I3 at the sides of spider arms 2B opposite those at which the blocks 27 are located, are angle brackets 2.8. Bolted at 29 to the brackets 28 are bearing plates 30 that are adjustable radially of the pulley and which have spaced studs 3I receiving the ends of helical compression springs 32. The springs 32 are interposed between the brackets 28 and the spider arms 26, and the other ends of these springs are received by studs 32 of radially adjustable bearing plates 33 similar to the bearing plates 3!) but bolted at 34 to `the spider arms 26. The radial adjustment of bearing plates 30 and 33 will of course effect corresponding adjustment of the springs 32 so as to vary, within limits, the leverage obtained by the action of springs 32 against the spider arms 26. At their outer ends, the spider arms 25 are provided with lugs 35 disposed to contact the stop blocks 2l. Obviously, for light service, one `spring 32 of each pair may be removed or eliminated. The purpose of the springs 32 is to yieldingly resist turning movement of the spider in the direction wherein the arms 23 move away from the stop blocks 21. In this way, the springs 25 provide a yielding driving connection between the spider and the disc I3 and they are retained in place by the studs 3| and 32'.

Slidable on the sleeve or hub 9 of the spider is an actuating cone 36 for pivoted clutch shoe operating levers 3l whose outer shorter arms are pivoted at 38 to the free ends of the clutch shoes 24. The longer arms of levers 31 carry at their inner ends rollers 39 that bear upon opposite sides of the cone 36 and are guided in brackets 40 secured to the inner side of disc I3. The pivots 4I of levers 3l are carried by disc I3 so as to be adjustable in a manner to provide adjustment of the clutch shoes relative to the drum or rim of pulley For this purpose, the pivots 4i are carried by clevises 42 having threaded stems 43 which freely pass through ears M carried by and projecting laterally from the disc I3, jamb nuts 45 being threaded on the stern d3 against opposite sides of the ears lli to secure the adjustment.

Helical tension springs 43 connect the inner longer arms of levers 3l with the respective shoes 24 and act to normally yieldingly release said shoes. However, movement of cone 26 toward disc I3 causes actuation of levers 31 in a direction to apply the shoes 2 or engage them with the clutch drum or rim of pulley e. As shown more clearly in Figure 4, the cone 36 is slotted to straddle the arms 2e at opposite sides of the spider sleeve or hub 9. Rigid with and projecting outwardly from opposite sides of the cone 33 are lugs il which carry pins 38 that are slidable through the spider arms 26 and have beveled inner ends. Fixed to disc I3 are cam plates 9 which are arranged in the path of the pins 3B. Thus, should rotation of shaft 5 be resisted to an extent sufficient to cause compression of springs 32, disc i3 will be caused to turn with pulley i5 by the previously applied shoes 23, and cam plates 49 will ride under the pins i3 so as to cause movement of the cone 35 away from disc I3, This shifts the tapered part of cone 36 toward the plane of rollers 39, thereby permitting swinging of levers 3l by springs SB in a direction to release the shoes 23 and permit free turning of the pulley S relative to shaft 5. A simple and eicient safety release clutch is thus provided between the pulley 6 and shaft 5.

In order that the driving connection between pulley 3 and shaft 5 may be manually released, the cone 26 has a shifting fork 50 engaged in a groove 5I thereof, and said fork 5U is provided with an operating rod 52 suitably adapted for manual actuation at a desired point. When the 4 cone 36 is actuated by rod 52 so as to be moved toward the disc I3, the levers 31 will be actuated by said cone to apply the shoes 24.

From the foregoing description, it is believed that the construction, operation and advantages of the present invention will be readily understood and appreciated by those skilled in the art, Minor changes may be made in details of construction, such as fall within the scope of the invention as claimed.

What I claim is:

1. A clutch comprising a driven shaft, a driving drum journaled on said shaft, a supporting Vmember journaled on said shaft within said drum, clutch shoes carried by said supporting rmember and adapted to engage the inner periphery of said drum, a spider including a hub secured on said shaft and provided with radially extending arms, springs carried by said supporting member and acting on the arms of the spider to yieldingly resist turning of the latter relative to said supporting member in one direction, levers pivoted on said supporting member and pivotally connected to said clutch shoes, springs connected to said levers and acting to disengage the clutch shoes from the drum, a cone slidable on the spider hub and engaged by said levers to actuate the latter for engaging the clutch shoes with the drum when moved toward the supporting member and for allowing the clutch shoes to be disengaged from the drum when moved away from said supporting member, cam plates carried by said supporting member, and pins carried by said cone and engageable by said cam plates for shifting the cone away from said supporting member when the spider is turned relative to the supporting member in onedirection.

2. The construction dened in claim l, wherein said levers are connected to corresponding ends of the clutch shoes, and links connecting the other ends of said clutch shoes with the supporting member.

3. The construction dened in claim l, wherein said cone is bifurcated to straddle the arms of said spider.

4. The construction deiined in claim l, in combination with stop members carried by said supporting member and arranged in the path of said spider arms to limit turning movement of the supporting member in the opposite direction by` the springs acting thereon.

5. The construction defined in claim 1, in combination with abutment plates carried by said supporting member, bearing plates carried by said abutment plates and the arms of the spider and provided with studs, said springs acting on the arms of the spider comprising compression springs having their ends received by the studs of the bearing plates.

6. The construction deiined in claim 1, in combination with abutment plates carried by said supporting member, bearing plates carried by said abutment plates and the arms of the spider and provided with studs, said springs acting on the arms of the spider comprising Compression springs having their ends received by the studs of the bearing plates, said bearing plates being adjustable radially of the clutch, and means to secure said bearing plates in adjusted position.

RUSH G. BROWN. 

